Could be coldest night of winter. Blame Siberia

Pat Mendoza walks along Wacker Drive. She is in Chicago for business. Temperatures dropped dramatically into the teens after record-setting warmth earlier in the week. (Nancy Stone, Chicago Tribune)

Arctic air has reclaimed the Midwest and is expected to bring the coldest nighttime temperatures of the winter -- and maybe the past two years.

The frigid blast will drive thermometer readings below zero across the Chicago area, with chills dipping to near 20 below by Friday morning. Daytime highs Friday may tie with the season's coldest readings to date, moving no higher than the low teens.

The record low for Feb. 1 is 3 degrees, set in 1895.

Chicagoans could see temperatures by Friday morning 66 degrees colder than Tuesday’s record-breaking 63-degree high. That would qualify as the largest four-day January temperature plunge on the books here since records began in 1871, easily surpassing the 61-degree four-day decline from Jan. 31 through Feb. 3, 1989.

The re-emergence of a cross-polar jet stream -- drawing Siberian air across the North Pole and into Canada -- is fueling the new cold outbreak. New snow is also contributing to its strength.

The Midwest's cover of snow was reinvigorated by Wednesday's snowstorm to the north and west. The system generated impressive accumulations from Iowa into northwest Illinois, Wisconsin and sections of Upper Michigan.

Totals as high as 10 inches were reported at Reedsburg, northwest of Madison, and 9 inches at Portage in Wisconsin. A 9-inch accumulation was observed at Watson, Iowa.

Even northwest Illinois got in on the action. Freeport reported a 4-inch snowfall but amounts as high as 6.5 inches fell at Scales Mound, 6 inches at Dubuque and 5 inches at Council Hill -- communities west of Rockford.

Chicago area totals included 0.6 of an inch at Huntley and Downers Grove, 0.4 of an inch at O’Hare International Airport and 0.3 of an inch at Midway late Wednesday evening.

Chicago gets another shot at snow as early as late Friday night. Recent model projections estimate totals from that disturbance may fall in the 1- to 3-inch range.